1. Field of Invention
This invention is related to navigational assistance systems. In particular, this invention is directed to systems and methods which provide tactile guidance through sensory supplementation.
2. Description of Related Art
A plethora of directional guidance systems are available with differing degrees of accuracy and scalability. For example, U.S. Pat. No. 3,902,687 to Hightower discloses a seat cushion for the pilot of an aircraft. The seat cushion has left and right vibrators that indicate to the pilot the deviation from a course selected via a radio navigation aid receiver. If the pilot is off course, one of the vibrators is actuated for indicating the corrective action needed, while the frequency of vibration indicates the error magnitude. This system can be further expanded by slipping an attachment over the pilot's leg. This attachment would again have vibrators to indicate deviations, for example, from a predetermined glide slope.
U.S. Pat. No. 3,736,651 to Hirsch discloses a pad which is mounted on the back of a swimmer. Embedded in the pad are indicators arranged in perpendicular rows. Upon sequentially energizing an indicator in a selected row, the person, i.e., swimmer, receives commands corresponding to a particular direction they should swim. H. Tan et al., "Tactile Displays for Wearable Computing," Massachusetts Institute of Technology Media Laboratory Perceptual Computing Section Technical Report No. 431, Proceedings of the International Symposium on Wearable Computers, 1997, discloses a wearable device for providing directions cues. Specifically, the system is designed to stimulate the back of a user. This system provides direction cues in the form of geometric patterns generated by sequentially energizing cells in a 3.times.3 vibrator array.
P. Probert et al., "Interfaces for Multi-Sensor Systems for Navigation for the Blind," Proceedings of the 1.sup.st European Conference on Disability, Virtual Reality and Assoc. Tech., Maidenhead, U.K., 1996 discloses wearable vibrating belts presented as part of a multi-modal navigation system for the blind. The wearable belt contains three sonar sensors for range finding of nearby objects and micro-navigation. Vibro-tactile cues are provided to the user via three vibrating motors in the belt. Thus, the belt is designed for use as a close range obstacle detection/avoidance device for the blind.
Additionally, there are many devices for forming a tactile readable message, including Braille characters and other various forms of graphic objects, such as lines and two-dimensional shapes formed by a matrix of pins. See, for example, U.S. Pat. No. 4,194,190 to Bareau and U.S. Pat. No. 4,473,356 to Fernando. Other generic actuating mechanisms include solenoids, as described in U.S. Pat. No. 4,191,945 to Hannen, electromagnetic devices, disclosed in U.S. Pat. No. 4,586,904 to Chlumsky and U.S. Pat. No. 4,871,992 to Peterson, piezoelectric devices, disclosed in U.S. Pat. No. 4,044,350 to Tretiakoff, and shape memory alloy actuators, disclosed in U.S. Pat. No. 5,685,721 to Decker.
Other methods for providing direction cueing use the Global Positioning Service (GPS). Mapless GPS systems, such as those described in U.S. Pat. No. 5,627,547 to Ramaswamy and U.S. Pat. No. 5,774,828 to Brunts, provide visual and audio direction cues to give directions to a user in outdoor environments.
Systems for overcoming disabilities are designed around substituting one sense for another. Arkenstone and VisuAide have jointly developed two new computer-based orientation systems for people with visual impairments. The first orientation system, ATLAS SPEAKS, enables maps to be accessible to blind people via voice synthesis or Braille displays. Users choose locations by address, by intersection, or by virtually "walking" there. Using detailed digital street maps, the user pilots a virtual pedestrian on the street network of the desired area. As the user explores the map, a talking user interface provides complete speech access to the system. This system also provides the ability to customize maps by adding points of personal interest or to choose paths between desired points. The system also allows the user to save the directions for such a path to, for example, a tape recorder, a note taker or printed hard copy.
The second orientation system is STRIDER. The STRIDER system integrates a GPS receiver with the digital map database from ATLAS SPEAKS. By combining and adding this capability to a portable notebook computer, a user gains access to information about their current location and the layout of the immediate area. Therefore, these systems provide orientation cues based on digital map data and satellite positioning information. Similar systems, such as "User Interface Designed for a Travel Aid for Blind People," http://www.psyc.nott.ac.uk/bmru/archive.html, 1995, by F. Michael, were developed in Europe.
L. Golledge, "Personal Guidance System for the Visually Impaired," Assets '94, Proceedings of the First Annual ACM Conference on Assistive Technologies, pp. 85-91, discloses a computer-based navigation system for the blind. This system consists of modules for determining a user's position and orientation, providing a computer map of the surrounding environment and a user interface built around a virtual acoustic display. For example, to indicate to a user that the administration building is off to the user's left, the user will hear the words "administration building" coming from their left.
H. Talkenberg, "The Electronic Guide Dog: A Technical Approach to In-Town Navigation," http://www.robots.ox.ac.uk:5000/.about.pjp/Rank/talkenberg.html, Avionik Zentrum Braunschweig GMBH & Co., KG Rebenring, Germany, March 1996, provides autonomous obstacle detection as the basic mobility function. Continuous position determination is included in the system for help functions, such as, for example, an automatic ambulance call. A mobile phone is built into the system for speech and data communication. This system further comprises a positioning system, a close range sensor, the mobile phone interface and a central station with a human operator who provides taxi calls, gives directions, etc. A button located on the user's system activates transmission of the position data to the central station. The operator can then identify, on a monitor collocated with the operator, the user's location by means of an electronic map. If necessary, instructions may be given directly to the user or an execution of a required service can be confirmed by a return signal to the user.
P. D. L. Meijer, "An Experimental System for Auditory Image Representations," IEEE Transactions on Biomedical Engineering, Vol. 39, No. 2, pp. 112-121, February 1992, discloses the vOICe system, which provides auditory displays that are intended as a substitute for vision. Image-to-sound mapping is used to generate the artificial vision. Specifically, the system was designed to provide auditory image representations within some of the known limitations of the human hearing system, possibly as a step towards the development of a vision substitution device for the blind. The application of an invertible one-to-one image-to-sound mapping ensures the preservation of the visual information.
TALKING SIGNS, disclosed in part in U.S. Pat. No. 5,616,901 to Crandall, and U.S. Pat. No. 5,623,358 to Madey, provide remote infra-red signs allowing people who are either print disabled or sight-impaired to know not only where a sign is located, but also the content of the sign. Specifically, unlike Braille, where raised letters or voice signs passively label some location or give instructions to some destination, TALKING SIGNS provides a repeating, directionally selective voice message which originates at the sign and is transmitted by infra-red light to a hand-held receiver carried by the user.
Similarly, the OPEN system disclosed in D. Irvin, "Talking Beacons," Possom Controls Ltd., http://www.robots.ox.ac.uk:5000/.about.pjp/Rank/irvine.html, is based on an infra-red transmission of speech. A network of infra-red beacons assist navigation through an underground station. Beacons are located at decision points, for example, where a side tunnel splits off from a main tunnel. The user is able to deduce the direction of the beacon from the characteristic of the received signal. Thus, the ability to be oriented to the beacon facilitates navigation across open spaces, and identifies the locations of key points, such as a ticket office. The users of the infra-red OPEN receivers are required to listen to the speech messages. The speech messages are continuously transmitted from the infra-red beacons. The OPEN receiver is normally silent, but plays a speech message to the user when an infra-red beam is within range of the receiver.